Your question is Diagnosing a Critical Bottleneck. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
How would you approach diagnosing a sudden bottleneck in a critical customer-facing operational process?
Explain how you would establish the baseline, isolate the constraint, distinguish symptoms from root causes, and coordinate with the teams involved. Describe how you would protect customers during the investigation, communicate status, select corrective actions, and verify that the process has returned to a stable state.